corliss



(Ho-Model.) .G H. OORLISS" Valve Gear for Steam Engines.

No. 235,744. Patented Dec. 21,1880.

NITE "rAr s ATENT I rrrcE.

VALVE-GEAR FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 235,744, dated December21, 1880.

Application filed J nne 14, 1880.

To all whom it may concern:

Be it known that I, GEORGE HENRY GOR- LIss, a citizen of the UnitedStates, residing at Providence, in the county of Providence and State ofRhode Island, have invcnted certain new and useful Improvements inValve- Gear for Steam-Engines, of which the followin g is aspecification.

The invention relates to the means for communicating motion to the steamand exhaust valves, respectively.

I use the circular sliding valves sometimes known as Corliss. operatedby turning alternately in opposite directions, in a manner analogous toa stop-cock. The exhaust-valves are operated with a positive continuouscon nection to the mechanism. The steam-valves are, under ordinaryconditions, opened by the m eehanism, liberated therefrom, and closed bythe force of a weight, spring, or atmospheric pressure.

It is important to so operate the connections that the valves will openand close rapidly, and to do this by a motion derived from an eccentric.I have, in a patent issued to me dated May 9,1876,N0. 177,099, shown amode of doing this by virtue of the different angular positions assumedby the valve-lever and by the links which connect each valve-lever tothe operating parts; but that mechanism requires multiplication of partsand increased chances of maladjustment. I have discovered andpractically worked out means for attaining the end in great perfectionwith a single eccentric and few parts.

The following is a description of what I consider the best means ofcarrying out the invention. The accompanying drawings form a part ofthis specification.

Figure 1 is a side elevation of a cylinder with my improved means of.communicating motion to the valve. Fig. 2 is an elevation at rightangles thereto.

Similar letters of reference indicate lik parts in both the figures.

Referring to the figures, A is the body of the cylinder, provided withfour valves-two steam-valves and two exhaust-valves. The levers aremarked, respectively, F.

G is a skeleton-lever turning on a center, 9, fixed on the side of thecylinder A, or of the (N0 model.)

fixed framing adjacent to the cylinder. This skeleton-lever is rocked bymeans of a rod, 9 operated by an eccentric, ('not represented,) andconnected to a pin, 9

The skeleton-lever G is branched, as represented. Each of the fourbranches carries a pin,g, which, by the arrangement of the parts, iscaused to move at each oscillation in the near vicinity of thecorresponding valve-shaft f. Each of the valve-levers F is joined to itsrespective pin 9 by a link,f.

The paths of the centers g at the upper end of the cylinder areindicated by dotted lines. So, also, are the paths of the ends of thevalve levers or arms F. It will be seen that the rocking of the singlelever G turns each of the valves to the proper extent, and also that byreason of the path of the pins 9 each near the shaft f of its respectivevalve, the valve is turned much more rapidly when the rocking lever isat the middle of its motion than when it is at either end of its motion.This gives the required rapid turning motion of the valve at the momentthe valve is being opened and being closed, with the required slowermotion at each end of its sweep; and this is effected and little chanceof maladjustment.

It will be understood that the steam-valves will usually close stillmore rapidlly than is provided by this motion, by virtue of their beingdetached and closed by selfacting means, (not shown,) but which may besimilar to those long approved on what are known as Corliss engines. Thequick motion in opening and closing and the slower motion at each end ofthe sweep of the valves is more particularly important with theexhaust-valves; but the quick opening is of considerable value also forthe steam-valves. The present invention attains this.

It will be observed that the left pins, g, which work theexhaust-valves, move nearer the axes f of their respective valves thanthe corresponding right pins, 9, which work the steamvalves.'Thisisimportant. Theexhaust-valves should open and close with a veryrapid m0- tion, and dwell with a slow motion in the open and closedpositions. The steam-valves should not possess the peculiarity of motionto the same extent. It is important in delicately adby the single leverG with few connections valve may be placed.

I can make the skeleton-lever G in various other forms, so long; as thecorrect positions of the centers 9, and consequently their correctmotions, are attained.

Modifications may be made in. the details by any good mechanic withoutdeparting from the principle or sacrificing the advantages of theinvention.

The steam-valves may partake in a higher or lower degree of the qualityof moving quickly in opening and closing. I prefer the proportions andconditions represented.

It will be understood that this invention does not interfere with any ofthe improvements of the valves and other parts of the steam-engine whichhave been used or may be used with this class of valves.

I claim as my invent1on In a steam-engine having circular slidingvalves, the skeleton-lever G, rocked as shown, and having pins g movingnear the axesfot' their respective valves, in combination withtheli'nksf, connecting such pinswith thevalvearms I", all arranged tooperate as and for the purposes heroin specified.

In testimony whereof I have hereunto set my hand, at Providence, RhodeIsland, this 9th day of June, 1880, in the presence of two 40subscribing witnesses.

GEO. H. (JORLISS.

Witnesses:

EDGAR PENNEY, ED. W. RAYNsFoRD.

